Diphenyl sulfone based multicolored cathodically coloring electrochromic materials with high contrast

A series of multicolored cathodically coloring electrochromic (EC) materials based on diphenyl sulfone (DPS) moiety were synthesized and characterized. Herein two electron donors, N1,N1,N3,N3-tetraphenylbenzene-1,3-diamine (TPA) and 1,3-di (9H-carbazol-9-yl)benzene (MCP), were employed to construct donor-acceptor (D-A) or donor-acceptor-donor (D-A-D) small molecules with DPS as the acceptor. These small molecules can achieve excellent EC properties, including multicolored electrochromism, high optical contrast over 90%, high coloration efficiency and good cyclic stability. Remarkably, the color of MCP-DPS could be switched from colorless to three primary colors gradually, containing green, magenta and yellow driven by the 3-step reversible reduction, meeting the requirements of full-color EC display. [Display omitted] •Diphenyl sulfone was first employed as the acceptor moiety to construct D-A or D-A-D electrochromic small molecules.•The diphenyl sulfone derivatives exhibit multicolored electrochromism with optical contrast over 90%.•Through slight modification of chemical structure, the electrochromic properties can be changed to a large extent.•Coloration efficiency can be improved by enhancing the intramolecular charge transfer interactions.